The only guy on the planet that might have 45mm stuff is Eric at Seventh Gear Karting… He has some 45mm axles on ebay, he might still have some sprockets.
If Eric doesn’t have a CRG part, you’re SOL!!!!
http://www.seventh-gear.com/store/contact.php
The only other option you have is to take a 40mm, bring it to a machine shop, and have them bore it to 45mm, you might not need the keyway rebroached either….
CR